Alzheimer's Disease
Dementia is an irreversible and progressive disorder of the brain. Symptoms include major loss of intellectual capacity and function. Alzheimer’s disease is the most common form of dementia and accounts for approximately 60% of all dementia cases. In New Zealand, it is estimated that Alzheimer’s disease affects up to 20,000 people over the age of 65, but only half of these will be diagnosed.
The degenerative changes that occur with Alzheimer's disease affect the areas that control thought, memory and language resulting in gradual signs and symptoms related to a person’s behaviour and mental function. Often, physical functions such as bowel and bladder control are also affected.
The condition is named after Dr. Alois Alzheimer the German physician who first described it in 1906. There is no cure for Alzheimer's disease and the condition is ultimately fatal.
Causes
In Alzheimer’s disease, brain cells start to deteriorate. The body attempts to stop this process by producing a protein called amyloid. However, amyloid deposits build up in the brain, leading to further deterioration. These deposits of amyloid are referred to as "plaques" and cause the brain cells to shrivel up and form "tangles", which in turn lead to changes in the brain structure and cause the brain cells to die. The formation of plaques and tangles also prevents some important chemicals in the brain, called neurotransmitters, from being produced. Over time the loss of brain cells causes the brain to shrink.
There is no known cause for Alzheimer's disease, but risk factors for developing the condition include:
- Increasing age
- Down's syndrome
- History of a head injury
- Risk factors for blood vessel disease such as smoking
- Family history of Alzheimer's disease
Males and females are affected equally.
Research studies have indicated that that the following factors may play an important role in the development of the condition:
Genetic factors
eg: The presence of, or changes to, certain genes.
Environmental factors
eg: Long term exposure to some environmental solvents eg: pesticides, glues and paints.
The role of autoimmune factors and certain viruses are also being studied.
Signs and Symptoms
With Alzheimer’s disease there is great individual variability as to the nature of symptoms experienced and the speed at which deterioration occurs. The types of behaviour change and the length of time symptoms are present are different for each person. The symptoms of Alzheimer's disease typically develop quite slowly. The time between the onset of the disease and death can range from five to 20 years.
Symptoms commonly experienced during the early stages of Alzheimer's disease include:
- Mild forgetfulness – especially short term memory loss
- Mood changes, including irritability & anxiety
- Difficulty processing new information and learning new things
- Loss of spontaneity and initiative
- Confusion about time and place
- Communication difficulties
- Decline in ability to perform routine tasks
As Alzheimer’s disease progresses the following symptoms may develop:
- Increasing short term memory loss and confusion
- Difficulty recognising family and friends
- Shorter attention span and feelings of restlessness
- Difficulty with reading, writing and numbers
- Possibly neglectful of hygiene
- Loss of appetite
- Personality changes (eg: aggression, significant mood swings)
- Requires increasing assistance with daily tasks.
Towards the later stages of the disease the following symptoms may be experienced:
- Inability to understand or use speech
- Incontinence of urine / faeces
- Inability to recognise self or family
- Severe disorientation
- Increasing immobility and sleep time
The changes brought about by Alzheimer's disease can be increasingly difficult for family members and friends. It is particularly difficult as the person’s condition deteriorates and they become unable to recognise loved ones.
Although a person loses many abilities as the disease progresses, it is often helpful to focus on the abilities that do remain, such as the senses of touch and hearing and the ability to respond to emotion.
Diagnosis
There is a no single test to diagnose Alzheimer’s disease. Diagnosis involves a full assessment of medical and psychiatric history to rule out other possible causes. Therefore a variety of tests are required to obtain a conclusive diagnosis.
Tests include:
- A neurological and physical examination
- Blood and urine tests
- Brain scans
- Mental status assessment to determine the level of mental deterioration
- Caregiver interview to determine the level of dependency
Scans to check brain structure and function may be recommended. The different types of scans used may include CT scanning (computerised tomography) and, MRI (magnetic resonance imaging).
Treatment
As there is no known cure for Alzheimer’s disease, treatment focuses on managing symptoms and supporting the person and their family. This may include:
- Treating medical conditions that may contribute to confusion or physical decline eg: lung disease or anaemia.
- Encouraging stimulating activities in order to encourage the person to continue their normal activities as much as possible.
- Providing memory aids and memory triggers such as calendars and written reminders.
- Encouraging social interaction to help prevent feelings of loneliness and depression.
- Contacting support groups that may be able to offer family/caregivers assistance.
- Encouraging regular routine to reduce confusion.
- Not smoking.
Medications
Medications such as sleeping tablets and tranquillisers may help to control symptoms such as sleeplessness and agitation. However they often cause increased confusion, so their use should be limited.
A group of medications called cholinesterase inhibitors have shown some effectiveness in slowing the progression of the condition in some people. These medications help prevent the breakdown of acetylcholine, a neurotransmitter responsible for memory. Examples of cholinesterase inhibitor medications are donepezil (Aricept) and rivastigmine (Exelon).
Research continues into the development of other medications for the treatment of Alzheimer's disease. Medications being investigated include those that prevent the build up of amyloid deposits in the brain, as well as looking at the use of some anti-inflammatory and hormone medications. Research also continues into the use of alternative therapies such as anti-oxidants like Vitamin E, selenium and some herbal extracts (ginko baloba in particular).
Further Support
Alzheimer's New Zealand (National Office and Resource Centre)
PO Box 3643
WELLINGTON
Freephone: 0800 004 001
Ph. 04 381 2362
Fax. 04 381 2365
Email: nationaloffice@alzheimers.org.nz
Website:
www.alzheimers.org.nz
References
Alzheimer Society of Canada (2004) The Three stages of Alzheimer Disease. Canada. Alzheimer Society of Canada
http://www.alzheimer.ca/english/disease/whatisit-intro.htm
Alzheimer’s Society of Canada (2004) Research Update. Alzheimer’s Society of Canada. http://www.alzheimer.ca/english/research/update04.htm
Alzheimer’s Disease International (2001) Drug Treatments in dementia. London: Alzheimer’s Disease Internationalwww.alz.co.uk
Everybody (2004) Alzheimer’s Disease. Auckland: MediMedia (NZ) Ltd
http://www.nzhealth.co.nz/everybody/docsa_c/alzheim.htm
Mental Health Foundation of New Zealand (2000) Dementia.
http://www.mentalhealth.org.nz/ctdisplay.php?ID=360&condition=12&p=&fp=
Last Reviewed – 15/02/07